The invention relates to a vehicle body having a first body component of fiber-reinforced plastic, and a second body component of fiber-reinforced plastic, which are adhesively bonded to one another by way of an adhesive layer and are subjected to shear stress and/or tensile stress in a main stress plane.
In vehicle bodies of modern vehicles, the body components are designed from fiber-reinforced plastic. Such body components are comparatively thin-walled and, correspondingly, have low rigidity and stability. It is correspondingly problematic for such body components to be connected so as to form a vehicle body which is stable or rigid, respectively, on the one hand, yet selectively resilient, on the other hand. It is known in principle here for the body components to be interconnected on adhesive faces by use of adhesive layers.
According to the invention, a vehicle body has a first body component of fiber-reinforced plastic, and a second body component of fiber-reinforced plastic, which are adhesively bonded to one another by way of an adhesive layer and, in a main stress plane, are shear-stressed and/or tensile-stressed. The adhesive layer is shaped by way of an adhesive flange. On the adhesive flange, the adhesive layer is obliquely oriented to the main stress plane at an angle between 30° and 60°. Particularly preferably, the adhesive layer according to the invention is obliquely oriented to the main stress plane at an angle between 40° and 50°, in particular at an angle of 45°.
Using the adhesive layer designed according to the invention, which on an associated adhesive flange is placed obliquely to the main stress plane in a targeted manner, joining in a shearing manner is avoided at the connection point of the two interconnected body components. At the same time, tensile head loads are also avoided, stress instead being introduced into the adhesive layer purely by shearing. Such an adhesive connection has a long life span and also high strength. The adhesive connection may also assume a sealing function. To this end it is particularly advantageous for the adhesive connection according to the invention to be designed as a structured adhesive connection, that is to say as an adhesive connection having a specially structured design of the adhesive faces, so as to include a sealing function. According to the invention, no second connection technique, such as screwing or riveting, and also no additional sealing process, is correspondingly required.
The body components according to the invention are preferably designed using plastics as a matrix, to which end both duroplastic as well as thermoplastic polymers may be employed. The comparatively cost-effective polyester resins, vinyl ester resins, and epoxy resins are used as duroplastic matrix systems. Thermoplastic fiber-composite materials may also be manufactured. In this case, mainly polyamides, polypropylenes, and polyethylenes are employed as matrix systems. Reinforcement materials or reinforcement fibers, respectively, are embedded in plastics of this type. According to the invention, mainly synthetic fibers from glass, carbon, and aramid, which are used as rovings, cross-laid structures, fabrics, or non-wovens, are used as a reinforcement material. In this way, the properties of the particularly shell-shaped body components may be varied in a wide range, both in an absolute manner as well as in a relative manner between the longitudinal and transverse direction of the body components.
As an adhesive method, according to the invention, an activator is preferably applied onto the body components prior to joining. The activator greatly accelerates the chemical reaction of the associated adhesive on the contact faces with the body components. Furthermore, adhesive is applied only to one body component, while the other body component is intensively heated. During subsequent joining of the body components a transition temperature, which is significantly above room temperature, is established. This temperature, in collaboration with the activator, leads to a very rapid reaction of the adhesive on the contact faces, such that the adhesive on the contact faces after a few seconds of holding time at this transition temperature builds up sufficient strength to prevent air from entering into the adhesive during subsequent increase of the temperature for curing the adhesive.
An A-pillar of a passenger cabin is preferably designed using the first and second body components of this type according to the invention. Such an A-pillar in terms of the main loading plane thereof, during normal operation of the vehicle, is stressed in the vertical direction and, in the event of a side impact, is stressed in the horizontal direction. The A-pillar thus has two main stress planes, one vertical stress plane and one horizontal stress plane.
Furthermore, on the vehicle body according to the invention, a side frame of a passenger cabin is advantageously designed using the first body component, and an annular-frame lower part of the passenger cabin is advantageously designed using the second body component. In the case of these two body components, again a vertical stress plane for the usual supporting stress and a horizontal stress plane for a side impact result as main stress planes.
According to the invention, furthermore, a third body component is preferably provided on the vehicle body, the adhesive layer of the third body component in relation to the first or second body component superimposing the adhesive layer between the first and the second body component. By way of this adhesive-layer arrangement, two adhesive layers are thus located on top of one another in a superimposing manner, a body component being located between the adhesive layers. The further two body components bear on the two outer sides of these adhesive layers. The body components here may only partially superimpose one another in the manner of roof tiles. Nevertheless, a “central” adhesive region, which acts as a connection hub for the body components, is established. Using the adhesive layers designed according to the invention, great rigidity can be achieved and, at the same time, particularly advantageous balancing of tensions during thermal expansion of the participating body components is enabled at this connection hub.
According to the invention, a side frame of a passenger cabin is preferably designed using the first and second body components, and a bulkhead or front end wall of the passenger cabin is preferably designed using the third body component. The side frame and the bulkhead are thus advantageously linked at this connection hub.
The invention is furthermore directed toward a vehicle body, in particular of the abovementioned type, having a first body component of fiber-reinforced plastic, and a second body component of fiber-reinforced plastic, which are adhesively bonded to one another by an adhesive layer and, in a main stress plane, are shear-stressed and/or tensile-stressed, wherein the adhesive layer is shaped by way of a curved adhesive flange. The adhesive layer of this type is selectively domed or is configured into a dome of the participating body components, respectively. Joining in a shearing manner and tensile head loads may also be avoided and introduction of load by shearing may be achieved using the design embodiment of this type. Furthermore, such an adhesive bond is advantageous in terms of an envisaged sealing function.
Attachment of a sill of a passenger cabin to a side frame is advantageously designed using the adhesive flange construction of this type, wherein a sill reinforcement of a passenger cabin is designed using the first body component, and a side frame of the passenger cabin is designed using the second body component.
Finally, the invention is also directed toward a vehicle body, in particular of the abovementioned type, having a first body component of fiber-reinforced plastic, and a second body component of fiber-reinforced plastic, which are adhesively bonded to one another by an adhesive layer, wherein the adhesive layer is particularly selectively designed to have a thickness of 1.4 mm to 1.6 mm. By way of an adhesive layer of this type, in particular in combination with the adhesive method explained above, a particularly advantageous balancing of tolerances of the participating body components within the adhesive layer is enabled. Furthermore, no second connection technique, such as screwing or riveting, and no additional sealing process, is required in this case.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.